• 1 tablespoon butter
• 1 cup whole or 2 percent milk or cream or half-and-half
• 3/4 teaspoon salt
• 1/8 teaspoon freshly ground pepper
• Pinch ancho chile powder
• Pinch nutmeg
• 1 pound Yukon Gold potatoes , peeled and sliced into 1/2-inch-thick rounds
• 1 pound sweet potatoes , peeled and sliced into 1/2-inch-thick rounds
• 3 tablespoons whole grain mustard
• 1 cup shredded Gruyere

Preheat oven to 400°F. Butter a shallow 2-quart gratin pan or ceramic baking dish.

In a large saucepan, combine milk, salt, pepper, chile powder, and nutmeg. Heat to boiling over a medium-high flame. Add potatoes and return to a boil; simmer a few minutes until mixture thickens slightly. Remove pan from heat; stir in mustard.

With a slotted spoon, transfer half the potatoes to gratin dish; place in an even layer. Sprinkle with 1/2 cup Gruyère. Top with remaining potatoes; pour milk mixture over potatoes and sprinkle with remaining 1/2 cup Gruyère. Bake 40 minutes, until potatoes are tender and top is golden.

244 calories, 9.3 grams fat, 5.3 grams saturated fat, 29 mg of cholesterol, 476 mg sodium, 31.1 grams carbohydrate, 3.4 grams fiber, 9.7 grams protein